Summary of the Animal Experiment
The Sencell device iteration resulting from the first animal experiments were evaluated in another animal experiment in pigs. Implantation of three modified Sencell sensors and one Dexcom® G4 control sensor was performed in the back and the neck area of three pigs (1 female, 2 male), respectively. After two days of equilibration and signal documentation, they received an i.v. glucose load of up to 100 mg/kg of dextrose. Reference measurements from capillary blood samples were performed using the YSI 2300 STAT Plus glucose analyser every 15 min for 5 h. In addition, the Dexcom 4 device was used as interstitial reference method.
During the first two days, six Sencell prototype devices were able to track glucose changes paralleling the results of the Dexcom Sensor over extended time periods. An example is shown in the figure below. Neither the Dexcom-Sensor, nor the Sencell sensor were able to reflect the very rapid intravenous blood glucose changes induced during the ivGTT in the plasma. This may rather represent the delayed and blunted glucose dynamics in the interstitial fluid during this time-period than can allow for any performance interpretation of the interstitial sensors.
In comparison to the previous results, deduction of movement artefacts as captured by the reference pressure chambers substantially reduced the noise level of the signals. The magnitude of the signals was in a predicted range and working sensors were matching G4 results. Although the body temperatures in the animals within three experimental days partially exceeded 39°C, the activity of ConA was preserved. No external signs of inflammation were observed.
In conclusion, improved performance of the actual sensor after recent design modifications could be demonstrated in vivo.
